After many attempts I succeded in becoming a Shutterstock contributor!
Submitting images to Shuterstock is simple, but you don't become a contributor if they don't accept your submissions.
Submissions rules are not so strict but you have to meet certain requirements in order to be accepted.
Moreover, non US citizens must submit a W8-something form and, to tell the truth, it was not easy for me.... I never loved fiscal stuff... I never understand such a complicated slang....
Anyway I did it!
Here you can find my images on sale on Shutterstock: click and you'll have a 20% discount!!!!